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Sprinkler zone starts, but then quits

I'm suspect of valve #1 and the Master Valve....
The first two solenoids' resistances were kinda low, and I didn't see were the master valve was tested for resistance.
I've had solenoids read well within their limits (for any given manufacturer) start shorting out after a period of time [from 10 seconds to as much as 3-5 minutes] - and the longer the solenoid had power, the less the resistance became finally breaking the circuit...
As a soleonid begins to short out the windings, the resistance becomes less and they start to heat up... and the more they heat up, the more windings become shorted...ad infinitum.
Way to check.... Jot down the resistances on all the valves including the master valve. Run the valves in queston and check 'em out right after the clock craps out... is the resistance is lower than it was when you checked it cold? 20 Ohms or less... replace the solenoid....
Good Luck.... Bill
tismaz.com

The Irrigation Specialist Mfg' Az.
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